A rotary tool, in short tool, serves to machine a workpiece. Given specific materials or machining methods, an additional supply of coolant or lubricant is necessary or at least advantageous. Since the thermal load is generally highest at the machining site, i.e., at the contact point of the tool on the workpiece, it is moreover expedient to deliver the coolant to this site. To this end, the tool often times comprises at least one coolant channel, by means of which a lubricant can also generally be delivered. The coolant channel extends thereby along the tool such that an outlet opening results at a suitable point. For example, in the case of a rotary tool, the outlet opening of the coolant channel can be arranged on the end surface side or in flutes of the rotary tool.
Particularly highly loaded rotary tools are moreover often times designed to be modular. Such a modular rotary tool generally comprises a carrier, to which is attached a cutting insert, which engages with the workpiece during operation. In this case, the carrier comprises a seat, into which the cutting insert is inserted. The coolant is generally conveyed in the direction of the cutting insert via a coolant channel introduced into the carrier, since the cutting insert is generally loaded more than the carrier and requires appropriate cooling. It is basically possible to guide the coolant channel exclusively through the carrier to the front side of the tool. In doing so, the coolant however cannot be conveyed arbitrarily close to the contact point. In DE 10 2014 108 220 A1, for example, a transfer of the coolant from the carrier to the cutting insert therefore takes place first in order to ultimately deliver the coolant via coolant outlets of the cutting insert on the end surface side.
To this end, the coolant channels first extend along the carrier and then transition into the cutting insert. The transition in this case takes place in the axial direction and at interfaces of the coolant channels arranged at the seat bottom of the seat.